Memory system and method of controlling memory system

A memory system comprising:

• a first memory including a plurality of physical blocks;
• a second memory that stores a first correspondence table in which a logical cluster address corresponding to an address assigned to data received from a host is correlated with a logical group number corresponding to a block group and a logical cluster number corresponding to a location within the block group, and a second correspondence table in which first physical block numbers corresponding to first physical blocks among the plurality of physical blocks are correlated with a first logical group number and second physical block numbers corresponding to second physical blocks among the plurality of physical blocks are correlated with a second logical group number;
• and
• a controller circuit, wherein the controller circuit is configured to:
• update the first correspondence table, when new data is written to one of the first physical blocks upon receiving a write command from the host, to correlate a first logical cluster address assigned to the new data with the first logical block number and a first logical cluster number;
• and
• update the second correspondence table so that the second physical block numbers corresponding to second physical blocks among the plurality of physical blocks are correlated with the first logical group number, when moving data which was written to the first physical blocks to the second physical blocks.